The U.S. Supreme Court has released the audio from the hearing on the California Proposition 8.More >>

The U.S. Supreme Court has released the audio from the hearing on the California Proposition 8.More >>

(RNN) – After two hours, the hearing on the Defense of Marriage Act before the U.S. Supreme Court is complete, and it is possible the high court could strike down the law.

Wednesday marked the second day of what could become a landmark week same-sex couples and for laws defining marriage.

According to SCOTUSblog, Justice Anthony Kennedy suggested the federal law is troublesome because it trumps states where same-sex marriage is legal.

"You are at real risk of running in conflict with the essence of state powers," Kennedy said. Kennedy often casts the tie-breaking vote on the court. In this case, he seems to be siding with the more liberal members of the court.

However, the court could dismiss the case on procedural grounds, which is less likely in this case than Tuesday's hearing on California's Proposition 8.

The decision on the case of United States v. Windsor, could have far-reaching implications because it challenges Section 3 of the Defense of Marriage Act. The 1996 law does not recognize same-sex marriages for all federal purposes.

Justice Ruth Bader Ginsburg said when legally married couples are being denied more than 1,100 federal benefits, "one might well ask, what kind of marriage is this?"

Paul Clement, the former solicitor general who argued for the law, told justices DOMA is only a "narrow" technical point, defining marriage for the purposes of federal law.

Ginsburg fought back and said the fact some legally married couples deserve benefits and others do not "diminishes what the state says is marriage." Couples would be left with "full marriage" on the one hand and "skim-milk marriage," on the other.

Because the Obama administration supports the rights of same-sex couples, the administration could not defend the law.

The first hour of the hearing Wednesday discussed whether House Republican leadership, who hope to legally defend DOMA, were allowed to defend the law at the hearing.

The case made it through appellate courts after Edith "Edie" Windsor challenged the law, enacted by President Bill Clinton.

Windsor had to pay more than $360,000 in federal taxes on the estate of her late spouse, Thea Spyer, because the U.S. government does not give same-sex couples the same tax-exempt status as heterosexual couples. That restriction includes couples from states where gay marriage is legal, such as New York, where Windsor and Spyer lived.

"We lived together for 40 years, we we're engaged with a circle diamond pin because I wouldn't wear a ring because I was still in the closet," Windsor said. "I am today an out-lesbian who just sued the United States of America, which is overwhelming to me."

The law also applies to federal laws affected by marital status, such as Social Security benefits, immigrants and insurance benefits for federal employees.

Roberta Kaplan, Windsor's lawyer, said she will tell the Supreme Court she is not seeking to establish a right for same-sex couples to marry but to require the federal government to recognize those marriages in states that permit them.

"The point with DOMA [is that] it's really unfair, unconstitutional and a violation of equal protection for the federal government for the first time in our country's history to have two classes of married couples," she told NPR in an interview before the hearing Wednesday.

Clinton and a senator who sponsored the legislation, Rob Portman, R-OH, have both spoken publicly in recent weeks voicing their desire that the Defense of Marriage Act be struck down.

Four federal district courts and two appeals courts have struck down the law's Section 3 as a result of lawsuits.

The law currently allows states the right to decide the legality of same-sex marriage.

Republicans in the U.S. House of Representatives assumed legal arguments for DOMA in. A number of religious organizations have legally filed support for DOMA and Proposition 8, among them: the U.S. Conference of Catholic Bishops, the Church of Jesus Christ of Latter-day Saints, the National Association of Evangelicals and the Family Research Council.

The arguments Tuesday in hearings for Proposition 8 - which challenges a state law - brought sharp back-and-forth arguments on subjects such as the role of marriage, procreation and adoption, so people on both sides are anticipating what will happen Wednesday.

Public reaction, including a number of rallies around the country and in front of the Supreme Court this week, showed how much acceptance of gay and lesbian unions has shifted.

Fifty percent or more of Americans said they favored legal recognition of same-sex unions in 2011 and 2012, according to Gallup polls. When the first survey was conducted in 1996, the year DOMA was passed, support of gay marriage was 27 percent.

White House Secretary Jay Carney urged caution when trying to gauge which position the court would side with in either case.

"As everyone, I will wait for whatever the decision is in the Supreme Court case hearings [Tuesday] and [Wednesday]," Carney said. "In recent history, there's been ample caution in predicting a Supreme Court decision, so I'll heed my own caution and not engage in that."

The Supreme Court announced Dec. 7 that it would hear arguments challenging DOMA, but a ruling on the case is not expected for several months. Following its usual procedure in such weighty cases, the justices usually do not render a decision until the nine-month session is almost complete.

The court Tuesday heard both sides of the argument in the challenge to California's Proposition 8 law, which placed a ban on same-sex marriage in the state in 2008. Despite that state supreme court's earlier ruling that preventing same-sex marriage was unconstitutional, voters approved the ban with a 52-percent majority.

Nine states and the District of Columbia now recognize same-sex marriages.